Abstract
3-Dimethylamino-2,2-dimethyl-2H-azirine (1) reacts with 3-methyl-2,4-diphenyl-1,3-oxazolium-5-olate (5a) to give a 1:1 adduct (7) in 88% yield. Its crystal structure has been determined by X-ray analysis (direct methods) and refined with 1056 structure amplitudes to R = 0.032. The crystal system is monoclinic, space group P21/c, with unit cell dimensions a = 10.663, b = 9.828, c = 18.592 A, and beta = 90.63°. It is obvious that 4-dimethylamino-5,5-dimethyl-2-[alpha-(N-methylbenzamido)benzyliden]-delta3-1,3-oxazoline (7) arises from an addition of 1 to the valence-polaromeric ketene form 5b of the mesoionic oxazolone 5a (Scheme 3).
Lukac, Josef